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The canard wing design has been successful over the years but there have been a
couple of changes that I have incorporated to reduce cost, reduce draughts and
to make a little safer, these are:
-
Improve the pins for the alignment tabs; and,
-
Improve the penetration of the fuselage side.
Alignment Tabs Pins
I had originally installed the canard alignment pins
strictly in accordance with the plans and had made a very tight
installation. The problem resulted the next day when I tried to remove
the canard, only to find that if the pins are a good fit into the
alignment tab bushings, it was almost impossible to remove the canard.
Removal requires that there is some 'slop' in the bushings for the
alignment pins. It took over an hour of wriggling and pulling to get the
canard off the fuselage. I decided that this was not a great design and
felt that there was a better way of doing this.
The drawing below indicated the standard way in which
the canard is attached and it can be seen that to elevate the forward
edge of the canard there is a need for significant play in the bushing imbedded in the
alignment tab.

The solution is relatively simple and can be seen in the
following drawing. In this instance a nut plate is installed on the
forward face of the alignment tab and a long AN3 bolt is installed
through the length of the doubler. A piece of bushing stock is inserted
and floxed in place to provide a hard surface onto which the bolt may react. The real
benefit of this design is in that it adds considerable support to the
rear end of the Canard and would provide additions support in the
unlikely event that a single main lift tab let go through fatigue. There is
no forward aft movement on the canard once this modification is made so
fatigue is probably reduced.

A photograph for the installation can be seen below
along with the hinge bearing for my forward hinging canopy.

Alternative Elevator Offset
I have never liked the double offset that the Ronce
Elevator uses. The offset is in place so that there is no large cut out
of the fuselage side resulting from the arc of the elevator torque tube
but why is the offset reinstated? I believe that it is only there to
maintain the same bearing support as those used outboard. I found that
the parts were expensive and since I had a lathe it was easier to
fabricate my own design. To this end it is necessary to fabricate the
following parts:
-
Excentric Shaft,
-
Bearing Holder; and,
-
Bellcrank Attachment.
The bronze bearing is a modified bought in unit found at
the local bearing shop. The excentric shaft is fabricated from 4130
steel stock and requires the use of the four jawed chuck to make the
excentricity.
The bearing holder was made as a 4130 steel weldment
but could easily be manufactured from 6061 Aluminium bar.
The bellcrank attachment was turned from 6061 Aluminium
bar stock.

The assembly drawing for the excentric shaft is shown
below. The bronze bearing is a press fit into the bearing holder and the
bearing holder is attached to a foam block that has been attached to the
underside of the canard and had some nut plates installed into the
block. Side views are also given in the subsequent drawings.



The photographs below show the installation but still
require some finishing glass work.


I authorize Chrissi & Randi of CG
Products to take this design and modify the design as they feel fit
to benefit the Canard community. Last Updated:
Monday December 04, 2006 |